PREPARATION OF BIODIESEL FROM WASTE COOKING OIL USI NG SINGLE STEP BATCH CATALYST WITH THE AID OF KOH AS A

CATALYST

NAJWA BINTI MOHD NOR

Faculty of Chemical Engineering and Natural Resource

University Malaysia Pahang

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CATATAN: * Potong yang tidak berkenaan.

** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasiberkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.

u Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan,

atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).

“Saya/Kami* akui bahawa saya telah membaca karya ini dan pada pandangan

saya/kami* karya ini adalah memadai dari segi skop dan kualiti untuk tujuan

Penganugerahan Ijazah Sarjana Muda Kejuruteraan Kimia.”

Tandatangan : ...........................................................

Nama Penyelia :SUMAIYA BINTI ZAINAL ABIDIN

Tarikh :16 MAY 2008

*Potong yang tidak berkenaan

iv

PREPARATION OF BIODIESEL FROM WASTE COOKING

OIL USING SINGLE STEP BATCH CATALYST WITH THE

AID OF KOH AS A CATALYST

NAJWA BINTI MOHD NOR

KA 04041

A thesis submitted in fulfilment of the requirements for the award of the

degree of Bachelor of Chemical Engineering

FACULTY OF CHEMICAL ENGINEERING

UNIVERSITI MALAYSIA PAHANG

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“I declare that this thesis is the result of my own research except as cited references.

The thesis has not been accepted for any degree and is concurrently submitted in

candidature of any degree”

Signature :………………………………..

Name of Candidate : NAJWA BINTI MOHD NOR

Date :16 MAY 2008

vi

DEDICATION

Special dedication to my beloved father, mother, brothers and sisters……………….

vii

ACKNOWLEDGEMENT

In preparing this thesis, I was in contact with many people, researchers,

academicians and practitioners. They have contributed towards my understanding and

thoughts. First and foremost, all praise and gratitude to Allah SWT for giving me

strength went through loads of difficulties to successfully finishing up my task. In

particular, I wish to express my sincere appreciation to my beloved supervisor, Cik

Sumaiya binti Zainal Abidin@Murad for valuable encouragement, guidance, critics

and friendship.

Not to be forgotten, all the lecturers, tutors and teaching engineers of Faculty

of Chemical & Natural Resources Engineering (FKKSA) for their support and

motivation during this project development, a deep thankfulness for everything and

may God bless all of us.

Last but not least, entire family especially my beloved father and mother,

En.Mohd Nor bin Hj.Mahmud and Pn.Siti Ashah bin Hj.Yahya and family members

for their continuous supports from the preliminary of this project till the end of it. All

my fellow friends should also be recognized for their support. Their tips and views are

indeed very useful

Wassalam

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ABSTRACT

Biodiesel is a cleaner burning diesel replacement fuel processed from natural,

renewable derived from biological sources such as used vegetable oils and animal

fats. The type of process that used to produce biodiesel is transesterification.

Transesterification is the commonly process that used widely compare to other

process. This process is important to convert free fatty acid (FFA) in oil to ester. In

this research, waste cooking oil is used as raw material with Potassium hydroxide

(KOH) as catalyst and methanol as a solvent. The reaction has been done in a water

bath. The parameter that been investigated were reaction time and catalyst

concentration while reaction temperature was fixed at 65̊C. Finally, the biodiesel

sample was tested on several parameters which are the yield, thin layer

chromatography (TLC), and moisture content. The analysis has been done using

Response Surface Methodology (RSM) to find the optimum condition based on

higher yield and TLC. It is to ensure its meet the standard requirement of ASTM

D6751 for biodiesel B100. The optimum result for higher yield is 73.38 minute

reaction time and using 1.33% catalyst concentration and the optimum result for

higher TLC is 90 minute reaction time and 0.5% catalyst concentration.

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ABSTRAK

Biodiesel adalah pengganti minyak pembakar diesel yang bersih yang diproses

dari alam semulajadi, ia dapat diperbaharui hasil daripada sumber biologis seperti

minyak sayuran dan lemak haiwan. Proses yang digunakan untuk menghasilkan

biodiesel adalah transesterification. Transesterification adalah proses yang selalu

digunakan secara meluas berbanding proses yang lain. Proses ini penting untuk

merubah asid lemak berlebihan ke minyak atau ester. Dalam eksperimen ini, minyak

masak yang telah digunakan dijadikan bahan mentah dan Potassium hydroxide (KOH)

sebagai mangkin dan methanol untuk pelarut. Tindak balas ini telah dijalankan

menggunakan water bath. Parameter yang harus dikaji adalah masa tindakbalas dan

kepekatan mangkin, manakala suhu tindakbalas ditetapkan pada 65̊C. Akhirnya,

sampel biodiesel akan diuji ke atas beberapa parameter iaitu jumlah hasil, kepingan

nipis kromatografi (TLC), dan kandungan air. Analisisnya pula menggunakan perisian

komputer Response Surface Methhodology (RSM) untuk mencari keadaan optimum

berdasarkan jumlah hasil dan TLC yang tinggi. Ini untuk memastikan hasil mencapai

norma piawaian ASTM D6751 untuk biodiesel B100. Data optimum untuk mencapai

hasil biodiesel tertinggi adalah 73.38 minit masa tindak balas dan 1.33% kepekatan

mangkin dan data optimum untuk mencapai TLC tertinggi adalah 90 minit masa

tindak balas dan 0.5% kepekatan mangkin.

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

TITLE PAGE i

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENT vii

LIST OF ABBREVIATIONS x

1 INTRODUCTION

1.1 Introduction 1

1.2 Background of Study 2

1.3 Problem Statement 3

1.4 Objective 4

1.5 Scope of Research 4

2 LITERATURE REVIEW

2.1 Biodiesel

2.1.1 Biodiesel Properties 5

2.1.2 Raw Materials 8

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2.1.2.1 Animal Fat 8

2.1.2.2 Vegetable Oil 9

2.1.2.3 Waste Cooking Oil 9

2.2 Process

2.2.1 Pyrolisis 10

2.2.2 Micro emulsion 11

2.2.3 Transesterification 11

2.3 Control Process Variables 13

2.3.1 Reaction Temperature 13

2.3.2 Ratio of Alcohol of Vegetable Oil 14

2.3.3 Amount of Catalyst 14

2.3.4 Reaction Time 16

2.3.5 Reaction Time Moisture and FFA 16

2.4 Catalyst 17

2.4.1 Alkali Catalyst 17

2.4.2 Acid Catalyst 18

2.5 Heterogenous and Homogeneous Catalyst 19

2.6 Response Surface Methodology 20

3 MATERIALS AND METHODS

3.1 Introduction 21

3.2 Materials

3.2.1 Raw Material 23

3.2.2 Chemical Material 23

3.3 Equipment 24

3.4 Experiment Procedure

3.4.1 Modeling of Process (Design Expert) 26

3.4.2 Pretreatment 27

3.4.3 Transesterification Process 27

3.4.4 Methanol Recovery and washing 28

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3.5 Analysis 28

3.5.1 Biodiesel yield 29

3.5.2 Thin Layer Chromatography (TLC) 29

3.5.3 Moisture content 31

3.6 Response Surface Methodology 31

4 EXPECTED RESULTS

4.0 Result 32

4.1 Optimization of Yield using Response Surface

Methodology (RSM) 33

4.2 Optimization of catalyst concentration using

Response Surface Methodology (RSM) 37

4.3 Optimization of moisture content using

Response Surface Methodology (RSM) 42

5 CONCLUSION & RECOMMENDATION

5.1 Conclusion 44

5.2 Recommendation 45

References 46

Appendices 48

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LIST OF ABBREVIATIONS

0C Degree Celcius

ANOVA analysis of variance

CCD Central Composite Design

DOE Design of Experiment

FFA free fatty acid

h hour

KOH Potassium Hydroxide

Min minute

ml mililiter

NaOH Sodium Hydroxide

RSM Response Surface Methodology

TLC Thin Layer Chromatography

CHAPTER 1

INTRODUCTION

1.1 Introduction

As world’s petroleum supplies are becoming constrained, attention has been

directed to find out alternative sources of fuels for engines. The non-renewable

nature and limited resources of petroleum fuels have become a matter of great

concern. After the 1973 oil embargo, it had been very important to study the

alternative sources of fuel for diesel engine because of the concern over the

availability and the price of petroleum based fuels. The present reservation of fuels

used in internal combustion (IC) engines including diesel will deplete within 40

years if consumed at an increasing rate estimated to be of the order of 3% per annum.

All these aspects have drawn the attention to conserve and stretch the oil reserves by

way of alternative fuel research.

Thus, the use of alternatives energy such as hybrid technology and hydrogen cell

requires extra modification to the vehicle engine. As a result, higher costs, longer

duration of time to develop were needed to upgrade this technology. Thus, research

on new energy sources, such as biodiesel has become more importance in recent

years.

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1.2 Background Of Study

Biodiesel is the alternative fuel substance that will replace the petrol one day. It

can be commercialize because it has more advantages compare to other source of

fuel. Only the little fossil energy is required to move biodiesel. Special pumps or

high pressure equipment for fuelling are not needed for this specification. In

addition, it can be used in conventional diesel engine, so we do not need any

upgrading or new purchasing for our engine.

In petrol, the scientists believe carbon dioxide is one of the main greenhouse

gases contributing to global warming. The 100% biodiesel will reduces carbon

dioxide emissions by more than 75% over petroleum diesel. If we use a blend of 20%

biodiesel, it will reduce carbon dioxide emission by 15%. Biodiesel also produces

less particulate matter, carbon monoxide, and sulphur dioxide emission which is all

air pollutants under the Clean Air Act.

This renewable fuel can directly replace petroleum product since it can be

used in conventional diesel engines. The biodiesel also can reduce the country’s

dependence on imported oil. Biodiesel offers safety benefits compare petroleum

diesel because it is much less combustible, with a flash point greater than 150°C,

compares to 77°C for petroleum diesel.

The energy that release for biodiesel is about same for petroleum diesel

(118,000 vs. 130,500BTUs). Therefore, engine torque and horse power remain

virtually same. Biodiesel is safer than petroleum diesel to handle or store. Biodiesel

does not produce dangerous vapors at normal ambient temperatures or room

temperatures, and it can be stored in the same containers and tank as petroleum

diesel.

The disadvantages of biodiesel is based on the sources that used to produced

the biodiesel, as an example if we produce biodiesel from waste cooking oil, the

process will also produce FFA (free fatty acid) as a side product. This biodiesel

3

production to commercialize is still along with the research to cover the

disadvantages.

The biodiesel used has grown dramatically during the last few years. The

Energy Policy Act was amended by the Energy Conservation Reauthorization Act of

1998 to include biodiesel fuel use as a way for federal, state, and public utility fleets

to meet requirements for using alternative fuels. In Malaysia there are plenty

company that starting this biodiesel production using Jarak fruit or the scientific

name is Jathopra curcas Linn, but during the production it still come along with

research with our local university like Universiti Malaysia Pahang (UMP).

1.3 Problem Statement

In Malaysia, government have gives subsidized to petroleum oil in

transportation sector. It shows that petroleum price is in unstable economy. Thus,

using waste cooking oil will make the biodiesel price is compatible than subsidized

petroleum diesel. The availability of raw material and cheaper cost are the main

criteria for choosing good raw material.

The high contain of fatty acid need to be synthesize using single step of

catalyzed process to prevent the high yield of soap. The single step is more

economical process compare to other process. The transesterification process is used

because its give high yield in reaction, reduce the production cost and low reaction

time rate. In the transesterification process, methanol will be use as alcohol solvent

because its cheaper compares other alcohol solvent.

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1.4 Objective

The main purpose of this research is to produce biodiesel from waste cooking

oil via single step batch catalyzed process and to find optimum condition using DOE

software to get higher yield and thin layer chromatography (TLC).

1.5 Scope Of Researchs

This research aim is a study in production of biodiesel using waste cooking

oil as the feedstock. To obtain the research objective, three elements have been

identified to be studied in this experiment. The three elements are:

i. To study the effect of reaction time and catalyst concentration. In the

transesterification process.

ii. To analyze several parameter such as yield, TLC and moisture content.

iii. To study single step catalyzed transesterification process.’

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CHAPTER 2

LITERATURE REVIEW

2.1.1 Biodiesel Properties

Biodiesel is other alternative fuel to replace petrol diesel that is produces by

chemically reacting a vegetables oil or animal fat. There are many benefits we get

from biodiesel in comparison to petroleum based fuels. It includes, the reduction of

CO emission by approximately 50% and carbon dioxide by 78% on a net lifecycle

basis. It happens because the carbon in biodiesel emissions is recycled from carbon

that was in the atmosphere, rather than the carbon introduced from petroleum that

was sequestered in the earth's crust. [Sheehan, 1998]. Biodiesel also contains fewer

aromatic hydrocarbons and biodiesel has a higher cetane rating than petrodiesel,

which can improve performance and clean up emissions compared to crude

petrodiesel.

The most important fact is biodiesel is biodegradable and non-toxic. The U.S.

Department of Energy confirms that biodiesel is less toxic than table salt and

biodegrades as quickly as sugar. In the United States, biodiesel is the only alternative

fuel to have successfully completed the Health Effects Testing requirements (Tier I

and Tier II) of the Clean Air Act (1990). The other advantages of biodiesel are, when

biodiesel were used in a blend with petroleum diesel, there are fewer formal studies

about the effects on pure biodiesel in unmodified engines and vehicles in day to day

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use. Fuel meeting the standards and engine parts that can withstand the greater

solvent properties of biodiesel is expected to run without any additional problems

than the use of petroleum diesel.

Properties

Biodiesel (vegetable oil methyl ester)

Peanut Soyabean Palm Sunflower Linseed Tallow

Kinematic viscosity at 37.8 1˚C(m2/s)

4.9 4.5 5.7 4.6 3.59 -

Cetane

number(̊C) 54 45 62 49 52 -

Lower

heating value

(MJ/l)

33.6 33.5 33.5 33.5 35.3 -

Cloud

point(̊ C) 5 1 13 1 - 12

Pour

point(̊ C) - -7 - - -15 9

Flash

point(̊ C) 176 178 164 183 172 96

Density(g/ml) 0.883 0.885 0.88 0.86 0.874 -

Carbon residue (wt%)

- 1.74 - - 1.83 -

Table 2.1 Properties of Biodiesel

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Figure 2.2 A scheme of the flow chart

The characteristics of biodiesel are close to diesel fuels, and therefore

biodiesel becomes a strong candidate to replace the diesel fuels if the need arises.

The conversion of triglycerides into methyl or ethyl esters through the

transesterification process reduces the molecular weight to one-third that of the

triglyceride, reduces the viscosity by a factor of about eight and increases the

volatility marginally. Biodiesel has viscosity close to diesel fuels. These esters

contain 10 to 11% oxygen by weight, which may encourage more combustion than

hydrocarbon-based diesel fuels in an engine. The cetane number of biodiesel is

around 50. The use of tertiary fatty amines and amides can be effective in enhancing

the ignition quality of the finished diesel fuel without having any negative effect on

its cold flow properties. Since the volatility increases marginally, the starting

problem persists in cold conditions. Biodiesel has lower volumetric heating values

(about 12%) than diesel fuels but has a high cetane number and flash point. The

esters have cloud point and pour points that are 15 to 258C higher than those of

diesel fuels.

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2.1.2 Raw Materials

The limitation of available sources for petroleum exploration is a strong

motivation to focus on renewable energy. There are few categorize for raw materials

to produce biodiesel which is animal fat, vegetable oil and waste cooking oil. Each

raw material have advantages and disadvantages.

2.1.2.1 Animal Fat

The fact that is biodiesel can produced from 100 percent animal fats and

fulfills the current EN 14214 for fatty acid methyl esters, as long as state-of-the-art

process technology is applied.When chemical properties of various feedstock

materials for biodiesel production are compared, the main difference between

vegetable oils like rapeseed oil and animal fats can be found in the diverse fatty acid

composition. While rapeseed oil and soybean oil have a high content of unsaturated

fatty acids, mainly oleic acid and linoleic acid, animal fats like tallow or lard have a

major content of saturated fatty acids (e.g., palmitic and stearic acid). The increased

amount of saturated fatty acids shows a reversed trend for two main fuelproperties.

While the oxidationstability of biodiesel derived from animal fats increases, the cold

temperature performance decreases with a rising content of saturated fatty acids.

Figure 1 shows the dependence of the content of saturated fatty acids in biodiesel –

without additives – on its cold filter plugging point (CFPP).

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2.1.2.2 Vegetable Oil

Vegetable oil can be divided into two categories, virgin oil and waste vegetable

oil. Virgin oil feedstock, rapeseed and soybean oils are most commonly used,

soybean oil alone accounting for about ninety percent of all fuel stocks; It also can be

obtained from field pennycress and Jatropha other crops such as mustard, flax,

sunflower, canola, palm oil, hemp, jatropha, and even algae show promise. The other

one is waste vegetable oil (WVO). The advantages of using vegetable oils as fuels

are it do not over burden the environment with emissions, vegetable oil’s production

requires lesser energy input in production, and simpler processing technology. While

the disadvantages of vegetable oil are these are not economically feasible yet and it

still need further R&D work for development of on farm processing technology.

Many advocates suggest that waste vegetable oil is the best source of oil to produce

biodiesel.

2.1.2.3 Waste Cooking Oil

Waste cooking oil is purified from fat of plant or animal origin, which is

liquid at room temperature. Proper disposal of used cooking oil is an important

waste-management concern. Oil is lighter than water and tends to spread into thin

and broad membranes which hinder the oxygenation of water. Because of this a

single litre of oil can contaminate as much as 1 million liters of water. Also, oil can

congeal on pipes provoking blockages, because of this, cooking oil should never be

dumped on the kitchen sing or in the toilet bowl. The proper way to dispose it is to

put it in a sealed non-recyclable container and discard it with regular garbage. Better

yet, cooking oil can be recycled. It can be used to produce soap and biodiesel.

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Figure 2.1 Content of Saturated Fatty Acid Chains

2.2 Process

2.2.1 Pyrolisis

Pyrolysis is the conversion of one substance into another by means of heat or

by heat in presence of a catalyst. The paralysed material can be vegetable oils,

animal fats, natural fatty acids or methyl esters of fatty acids. The pyrolysis of fats

has been investigated for more than 100 years, especially in those areas of the world

that lack deposits of petroleum. Many investigators have studied the pyrolysis of

triglycerides to obtain products suitable for diesel engine. Thermal decomposition of

triglycerides produces alkanes, alkenes, alkadines, aromatics and carboxylic acids

[Ma et al, 1990]

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2.2.2 Micro Emulsion

The problem of the high viscosity of vegetable oils can be solving by

emulsification with solvents such as methanol, ethanol and 1-butanol. An

emulsification is defined as a colloidal equilibrium dispersion of optically isotropic

fluid microstructures with dimension generally in the 1–150 nm range, formed

spontaneously from two normally immiscible liquids. They can improve spray

characteristics by explosive vaporization of the low boiling constituents in the

micelles. Short term performance of micro-emulsions of aqueous ethanol in soybean

oil was nearly as good as that of no. 2 diesel, in spite of the lower cetane number and

energy content [Srivastava et al, 2000]

2.2.3 Transesterification

Transesterification is the process of exchanging the alkoxy group of an ester

compound by another alcohol. The reactions are often catalyzed by an acid or a base.

Transesterification is crucial for producing biodiesel from biolipids.

Transesterification is the process triglycerides react with an alcohol, generally

methanol or ethanol to produce esters and glycerine [Miguel et al., 2001]. A catalyst

is added to the reaction to make it possible. The catalyst is usually used to improve

the reaction rate and yield. Since the reaction is reversible, excess alcohol is required

to shift the equilibrium to the product side. Among the alcohols that can be used in

the transesterification process are methanol, ethanol, propanol, butanol and amyl

alcohol [Ma et al, 1990]. Alkali-catalyzed transesterification is much faster than acid

catalyzed transesterification and is most often used commercially [Ma et al, 1990].

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Figure 2.2 Transesterification Process

R1, R2, R3, R’ represent various alkyl group. The process of

transesterification brings about drastic change in viscosity of vegetable oil. The

biodiesel thus produced by this process is totally miscible with mineral diesel in any

proportion. Biodiesel viscosity comes very close to that of mineral diesel hence no

problems in the existing fuel handling system. Flash point of the biodiesel gets

lowered after esterification and the cetane number gets improved. Even lower

concentrations of biodiesel act as cetane number improver for biodiesel blend.

Calorific value of biodiesel is also found to be very close to mineral diesel [Agarwal,

2001].

Diesel engine can perform satisfactory for long run on biodiesel without any

hardware modifications. Twenty percent biodiesel is the optimum concentration for

biodiesel blend with improved performance. Increase in exhaust temperature

however lead to increased NOx emissions from the engine. While short-term tests are

almost positive, long-term use of neat vegetable oils or their blend with diesel leads

to various engine problems such as, injector coking, ring sticking, injector deposits

etc. [Muniyappa et al., 1996]. High viscosity, low volatility and a tendency for

polymerization in the cylinder are root causes of many problems associated with

direct use of these oils as fuels.